RU2761798C1 - Submersible pump with bypass for liquid injection - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry, and in particular to devices for lifting to the day surface of products from wells with the possibility of pumping liquid into the sub-packer space in downhole conditions. A submersible pump with a bypass channel for liquid injection comprises a submersible borehole pump lowered on a pipe string, equipped with a liner at the bottom and a bypass channel communicated with the liner and the inner space of the pipe string above the pump. The bypass channel is equipped with a spring-loaded adjustable valve that closes the fluid flow in the bypass channel between the liner and the internal space of the pipe and maintains the pressure in the pipe string arising from the pump operation. The liner is equipped with a packer externally positioned above the reservoir. An overflow channel is made inside the liner, which communicates above the packer and subpacker spaces of the well and is equipped with a bypass spring-loaded valve that opens only at excessive pressure in the subpacker space during fluid injection through the bypass channel.

EFFECT: providing the ability to pump fluid into the formation through the pipe string without removing the pump and flushing the bottomhole zone.

1 cl, 1 dwg

Description

The invention relates to the oil and gas industry, and in particular to devices for lifting to the day surface of products from wells with the possibility of pumping liquid into the sub-packer space in downhole conditions.

Known submersible borehole pumping unit for oil production, safety and check valves of submersible borehole pumping unit and a device for sealing the annular gap in the well (patent for PM RU No. 60613, E21B 43/08, publ. Bull. No. 3 from 27.01.2007. ), which is designed as a submersible borehole pumping unit for oil production, including a submersible borehole pump, means for filtering the pumped liquid, at least from particles of mechanical impurities, located before the pump intake in the direction of movement of the pumped liquid, a safety valve configured connection with the annular space of the cavity of the pumping unit located behind the filtration means along the direction of movement of the pumped liquid, when the pressure in the annular space is higher than a predetermined value, while it is equipped with a check valve located downstream of the pump along the direction of movement of the pumped liquid and designed to limit the flow of liquid , read pumping from the tubing string into the pump cavity when it stops, and it also contains means for ensuring the flow of the pumped liquid to receive the pump through the means for filtration, the means for ensuring the flow of the flow include a hollow cylindrical casing made to be placed inside the submersible electric motor of the pump unit in such a way that it is possible to move the flow of the pumped liquid through the gap between the casing and the electric motor; the possibility of fastening from the side of the lower open end of the casing to ensure the movement of the formation fluid flow through the lower end of the liner, on which the receiving unit of the pumping unit is made, including at least one filter, and a safety valve pan.

The disadvantages of this device are the impossibility of pumping reagents (especially abrasive and chemically aggressive), since the throttling hole in the valve has a small section and does not provide a strong fluid flow, while this flow must pass through the pump, as well as a decrease in the efficiency (efficiency) of the pump especially in wells with productive formations located at a depth of more than 1000 meters, the presence of a throttling hole in the check valve creates a constant back pressure, which increases the internal losses in the pumps, and after stopping the pump, it is necessary to fill the pipe string with liquid, from which the liquid is drained to clean the filter.

The closest in technical essence is a submersible pump with a filter that can be cleaned in the well (patent RU No. 2415253, E21B 43/00, E21B 37/08, E21B 34/06, publ. Bull. No. 3 dated January 27, 2007), including itself a submersible borehole pump lowered on a pipe string, which is located in a hollow cylindrical casing, hermetically and rigidly fixed from above and allowing the flow of the pumped liquid to flow through the gap between the casing and the pump, a hollow cylindrical liner fixed on the side of the lower open end of the casing and equipped in the lower parts by a filter, and a check valve located downstream of the pump in the direction of movement of the pumped liquid, and the casing is made in communication with the inner space of the pipe string above the check valve, which flows from the bottom up, and is equipped with a spring-loaded adjustable valve that blocks the flow of liquid in the casing between the pump inlet and the communication with the inner space of the pipe and holding the pressure in the pipe string caused by the operation of the pump.

The disadvantage of this pump is a narrow field of application, since it is not designed to work with installations equipped with a packer above the productive formation (there are most of such wells in the fields of the Republic of Tatarstan - RT), due to the impossibility of pumping liquid into the sub-packer space and flushing the sub-packer space in the presence of reagents or abrasive substances included in the pumped liquid.

The technical objective of the present invention is to create a submersible pump with a bypass channel for fluid injection, which allows injection of fluid into the formation through the pipe string without removing the pump with flushing the bottomhole zone by installing a packer on the liner above the productive formation, equipped with a bypass channel with a bypass spring-loaded valve that opens only at excessive pressure in the under-packer space when pumping liquid through the bypass channel.

The technical problem is solved by a submersible pump with a bypass channel for liquid injection, including a submersible borehole pump lowered on a pipe string, which is equipped with a liner from the bottom and a bypass channel communicated with the liner and the inner space of the pipe string above the pump and equipped with a spring-loaded adjustable valve that closes the liquid flow in the bypass the channel between the liner and the inner space of the pipe and holding the pressure in the pipe string arising from the action of the pump.

The novelty is that the liner is equipped on the outside with a packer installed above the productive formation, and from the inside with an overflow channel that communicates above the packer and subpacker spaces of the well and is equipped with a bypass spring-loaded valve that opens only when there is excess pressure in the underpacker space during fluid injection through the bypass channel.

The drawing shows a diagram of a submersible pump.

A submersible pump 1 with a bypass channel 2 for pumping liquid includes a submersible borehole pump 1 lowered on a pipe string 3, which is equipped with a liner 4 from the bottom and a bypass channel 2 communicated with the liner 4 and the internal space of the pipe string 3 above pump 1 and equipped with a spring-loaded variable valve 5 blocking the fluid flow in the bypass channel 2 between the liner 4 and the internal space of the pipe 3 and holding the pressure in the pipe string 3 arising under the action of the pump 1. The liner 4 is equipped on the outside with a packer 6 installed above the productive layer 7 of well 8, and from the inside with a crossflow channel 9, communicating above-packer 10 and below-packer 11 spaces of well 8 and equipped with a bypass spring-loaded valve 12, which opens only at excessive pressure in the below-packer space 11 during pumping liquid through the bypass channel 2. Pump 1 can be used of any known design, for example, an electric centrifugal pump (ESP), rod submersible pump (SRP) or the like Packer 1 with shank 4 can be used in any known design, for example, see patents RU No. 2105864, 56159, 101487 or the like. The liner 4 can be additionally equipped with a filter (see patent RU No. 2415253 or the like - not shown) or not, depending on the contamination of the formation product 7 by mechanical impurities.

Structural elements and process connections that do not affect the performance of pump 1 are not shown in the drawing or are shown conditionally.

The bypass pump works as follows.

The interval (depth) of the well 8, in which the pump 1 and the pressure in the formation 7 will be installed, are preliminarily determined. Based on this, the pressure that the pump 1 will create to lift fluid from the well 8 to the day surface (not shown) is calculated. Then, the valve 5 is adjusted to maintain this pressure created by the pump 1 in the pipe string 3 with a margin of 5-10% (+ 5-10%), for which the spring 14 is pressed against the stop 13 (for example, with a screw - not shown), and adjusting the bypass valve 12 to maintain this pressure created by the formation 7 in the shank 4 with a margin of 3-7% (+ 3-7%), for which the spring 16 is pressed against the stop 15 (for example, by the corresponding screw - not shown). If necessary, to determine the pressure held by valve 5 and bypass valve 12, they are tested on a bench with subsequent appropriate adjustment.

After assembling the pump 1 with the bypass channel 2 and the liner 4, equipped with the packer 6 and the bypass channel 9, it is lowered on the pipe string 3 into the well 8 in the installation interval. Then the packer 6 is installed above the layer 7.

The packer 6 divides the inner space of the well 8 into above-packer 10 and below-packer 11 spaces.

If a plug-in pump 1 is used, then first the liner 4 with a lock (not shown) is lowered at the top and the packer 6 is installed above the formation 7. Then pump 1 with a nipple (not shown) is lowered at the bottom for tight interaction with the liner 4 lock.

After starting pump 1 from the wellhead (ESP - by cable - not shown, SRP - by giving reciprocating movement to the rods with a plunger - not shown, or the like), the production of formation 7 through liner 4 under the action of pump 1 along the string pipes 3 rises to the day surface (not shown). In this case, valves 5 and 12 are in a closed state.

During operation of the pump 1, a vacuum is created in the under-packer space 11, which promotes the release of gas from the production of formation 7, accumulating under the packer 6. This leads to its accumulation under the packer 6, breaking through the liner 4 to the pump 1 inlet, reducing its efficiency (efficiency ), and the ESP in the absence of liquid may fail. Also, gas, due to its compressibility, reduces the efficiency of pump 1 in the form of a sucker rod pump, since it works periodically, and gas impedes the inflow of products into the sub-packer space 11 from reservoir 7. The filter (if any) of the liner 4 may also be clogged.

During long-term operation by pump 1, the reservoir 7 may change the filtration properties, water breakthrough from it to the pump 1 inlet and / or decrease in productivity (for example, oil). Then, in order to increase the profitability of production from reservoir 7, it is necessary to carry out a number of measures to increase oil recovery (EOR) of reservoir 7 by injecting appropriate reagents (acid compositions, bridging compositions, and / or the like). The volume of the required reagent for injection into reservoir 7 is determined by the technologists for EOR (the authors do not pretend to be)

To squeeze out gas from the under-packer space 11 or flush the filter of the liner 4, pump 1 is stopped, opened at the packer space 10 at the wellhead, and in the pipe string 3 by pumping liquid, an overpressure is created (for example, with a wellhead pump - not shown), exceeding the value of the stock of valves 5 and 12 by pressure, which in the installation interval of pump 1 will be sufficient to compress the springs 14 and 16 to open the corresponding valves 5 and 12, ensuring the circulation of liquid from the pipe string 3 through the bypass channel 2, the shank 4, the sub-packer space 11 and the overflow channel 9 into the above-packer space 10 and further to the surface. In this case, the gas is removed from the under-packer space 11 and / or the liner filter 4 is cleaned.

To inject reagents into reservoir 7, pump 1 is stopped, at the packer space 10 at the wellhead is left closed, and in the pipe string 3 by pumping the reagent an overpressure is created (for example, with a wellhead pump - not shown), which exceeds the value of the valve 5 pressure reserve, which in the installation interval pump 1 will be sufficient to compress the springs 14 for opening the valve 5, ensuring the injection of the required volume of reagent into the reservoir 7 using the required volume of displacement fluid (fresh water, mineral water, industrial water, etc.) selected by the technologists conducting the EOR. After technological exposure sufficient for the effect of the reagent on the formation 7, the above-packer space 10 at the wellhead is opened, and in the pipe string 3 by pumping liquid, an excess pressure is created (for example, with a wellhead pump - not shown), which exceeds the value of the stock of valves 5 and 12 by pressure, which in installation interval of pump 1 will be sufficient to compress the springs 14 and 16 to open the corresponding valves 5 and 12, ensuring the circulation of fluid in a volume of at least the volume of well 8 from the productive formation 7 to the wellhead 8 from the pipe string 3 through the bypass channel 2, liner 4, sub-packer space 11 and overflow channel 9 into the above-packer space 10 and further to the surface. In this case, the residual reagents are washed out from the sub-packer space 11 and exclude them from entering the inlet of pump 1, since this can lead to failure of pump 1 when it is turned on.

Upon completion of the liquid circulation operations, the wellhead pump is disconnected from the pipe string 3, the above-packer space 10 is closed at the wellhead, and pump 1 is put into operation, operating the reservoir 7 of the well 8 in normal mode.

The proposed submersible pump with a bypass channel for liquid injection makes it possible to additionally pump liquid into the formation through the pipe string without removing the pump with flushing the bottomhole zone by installing a packer on the liner above the productive formation, equipped with a bypass channel with a bypass spring-loaded valve, which opens only at excessive pressure in under-packer space when pumping liquid through the bypass channel.

Claims (1)

Submersible pump with a bypass channel for pumping liquid, including a submersible borehole pump lowered on a pipe string, which is equipped with a liner at the bottom and a bypass channel communicated with the liner and the internal space of the pipe string above the pump and equipped with a spring-loaded variable valve that closes the liquid flow in the bypass channel between the liner and the inner space of the pipe and holding the pressure in the pipe string arising under the action of the pump, characterized in that the liner is equipped on the outside with a packer installed above the productive formation, and from the inside with an overflow channel that communicates above the packer and below the packer space of the well and is equipped with a bypass spring-loaded valve that opens only with excess pressure in the under-packer space during liquid injection through the bypass channel.

Images